JP2002342255A - Device for connecting usb device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the inafility of simultaneously providing a service even at sharing of a USB device by a plurality of USB hosts by a connection switching device, since the USB specifications are one-to-many commutation between the USB hosts and the USB device. SOLUTION: This device is provide with a plurality of pseudo-USB device functioning parts A, B, and C respectively connected to a plurality of USB hosts A, B, and C, one pseudo-USB host part 215 connected to USB devices A and B; a descriptor converting part 213 for generating each descriptor group describing a service to be provided to each USB host by the USB devices, and for setting the descriptor groups in those pseudo-USB device functioning parts; and a data transfer managing part 212 for controlling data transfer between those pseudo USB device functioning parts and the pseudo-USB host part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plurality of USB (Univ.
eral Serial Bus) relates to a USB device connection device connected between a host and one or more USB devices.

[0002]

2. Description of the Related Art The USB standard for standardizing the peripheral device interface of a personal computer has been widely used as a standard bus interface to be mounted on a personal computer since the standard support by an operating system was provided.

The USB standard defines a communication system having a tree structure. In other words, the USB system has a master function such as data transfer management and has only one USB host located at the top of the tree structure, a hub located at a branch point of the tree structure, and a USB located at the end (leaf) of the tree structure. It is composed of devices, and defines a one-to-many communication method between a USB host and a USB device.

Therefore, in order to use one USB device from a plurality of USB hosts, it is necessary to change the connection of the cables. 1946
There is one disclosed in Japanese Patent Publication No. 49-49.

In a conventional USB device connection device as disclosed in the publication, when a USB device is shared by a plurality of USB hosts, a switching device having a built-in hub or the like is used to connect a USB host connected in parallel. A method of selecting and communicating at any time is adopted.

FIG. 8 is a conceptual diagram illustrating an example of a conventional method for sharing a USB device from a plurality of USB hosts. In FIG. 8, USB hosts 801, 802, and 803 are connected to upper ports and USB devices 804, 805, and 806 are connected to lower ports for the switching device 800. The switching control unit 807 and the route switching unit 808 included in the switching device 800 provide one U
One selected USB host is associated with the SB device.

[0007]

However, in the above-mentioned conventional method, one USB host is provided from a plurality of USB hosts.
Devices cannot be accessed simultaneously. That is, according to the USB standard, a USB device
In order to share a USB device from a plurality of USB hosts, the host must be unique. Therefore, it is necessary to confirm with a control signal or the like that another USB host is not accessing a target USB device, and perform a process of switching connections. is necessary.

Further, in the above-mentioned conventional switching device, the USB host can only be connected in parallel to the switching device, and cannot provide a hierarchical role between the USB hosts.

[0009] The present invention solves the above-mentioned conventional problems, and provides a USB device connection device that enables a plurality of USB hosts to share one USB device and simultaneously obtain services provided by the USB device. The purpose is to do. A further object of the present invention is to provide a USB device connection device which enables a USB host to be hierarchically extendedly connected to a single USB device.

[0010]

In order to achieve the above object, a USB device connection apparatus according to claim 1 of the present invention comprises a plurality of USB hosts (USB hosts A, B, C) and one or more USB hosts. In a USB device connection device connected to a USB device (USB devices A and B), a plurality of pseudo-USs connected to the plurality of USB hosts, respectively.
B device function unit (pseudo USB device function unit A, B,
C) and one pseudo U connected to the USB device
An SB host unit (pseudo USB host unit 215);
A descriptor conversion unit (descriptor conversion unit 213) that generates a descriptor group describing a service provided by the SB device to each of the USB hosts and sets the descriptor group in the pseudo USB device function unit; and the plurality of pseudo USB device function units. A data transfer management unit (data transfer management unit 212) for controlling data transfer between the virtual USB host unit and the pseudo USB host unit.

According to the first aspect of the present invention, the USB host is associated with a pseudo USB device function unit that holds a descriptor group corresponding to a service, and the USB device is connected with a pseudo USB host unit. By controlling the data transfer between them, the connected USB host and USB device
A service that can be provided by a USB device can be simultaneously provided to a plurality of USB hosts without difficulty while satisfying the SB standard.

According to a second aspect of the present invention, in the USB device connection apparatus according to the first aspect, the descriptor conversion unit provides a service provided to a USB host from a group of descriptors set in the USB device. Is selected in accordance with the above, the conversion is performed as necessary, and the reconstructed descriptor group is
This is set in the SB device function unit.

According to the second aspect of the present invention, the plurality of USB hosts can be connected to the USB host by reconfiguring the group of descriptors set in the pseudo USB device function unit according to the service provided to the USB host.
Based on the B standard, the USB device can be presumed to be occupied and connected.

According to a third aspect of the present invention, there is provided a USB device connection apparatus according to the first or second aspect, wherein a USB host application execution function (application control unit 214) is incorporated. .

According to the third aspect of the present invention, the USB device connection device has a built-in application execution function of the USB host, so that the USB device connection device can act as a host computer. A configuration in which the USB host is hierarchically expanded and connected can be adopted.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration method of a USB system using a USB device connection device according to an embodiment of the present invention.

In FIG. 1, reference numeral 100 denotes a US according to the present invention.
This is a USB data conversion device that embodies a device B connection device, and USB hosts 101, 102, 103
However, USB devices 104 and 105 are connected to lower ports. The USB data conversion device 100 performs control such as descriptor conversion and data transfer management between the USB host and the USB device in order to distribute services provided by the USB device.

In the USB standard, a service provided by a USB device is composed of one or more interfaces described by a descriptor, and a service is associated with a USB host by an interface number.

In FIG. 1, the USB device 104 supports interfaces # 0 to # 7, and the service S1
Interfaces # 0 to # 2 configuring the service S2 are provided to the USB host 101.
3 to # 5 are provided to the USB host 102, and interfaces # 6 to # 7 constituting the service S3 are provided to the USB host 103.
Is associated with. USB device 105 is USB
Although connected to the data converter 100, it is not associated with a USB host.

As described above, a plurality of services that can be provided by a USB device can be associated with different USB hosts according to interface numbers. In FIG. 1, U
Services S1, S2, S provided by SB device 104
3 are assigned to the USB hosts 101, 102, and 103, respectively.

Next, a specific configuration example of the USB device connection device will be described. FIG. 2 shows a US according to an embodiment of the present invention.
It is a block diagram showing composition of a B apparatus connection device.

In FIG. 2, reference numeral 200 denotes a US according to the present invention.
This is a USB data conversion device that embodies the device B connection device, and the USB host 201, 202, 203
However, USB devices 204 and 205 are connected to lower ports.

The USB data converter 200 is a pseudo-US
B device function units 206, 207, 208, pseudo USB
Host unit 215, CPU 211, data transfer management unit 21
2. Descriptor conversion unit 213, application control unit 214, and buses 209 and 210 connecting them.

Reference numerals 216, 217, and 218 denote interrupt signals from hardware resources included in the pseudo USB device function units 206, 207, and 208, respectively.
9, 220 are application control units 21 respectively.
4. An interrupt signal from a hardware resource included in the pseudo USB host unit 215.

The pseudo USB device function units 206 and 20
7 and 208, USB host 2 connected to the upper port
01, 202, and 203, and functions as a USB device for a USB host. Also, pseudo US
The B host unit 215 includes a plurality of U ports connected to lower ports.
It functions as a USB host for the SB device and can control them.

Further, the data transfer management unit 212
The data transfer route between the SB device function unit and the pseudo USB host unit is managed, and the descriptor conversion unit 213 generates a descriptor dedicated to the pseudo USB device function unit. The application control unit 214 manages an application mounted on the USB data conversion device 200.

Next, the processing of the descriptor conversion unit 213 for setting the descriptor group corresponding to the service in the pseudo USB device will be described with reference to FIGS. FIG. 3 is a flowchart showing the procedure of the descriptor conversion process, and FIG. 4 is a conceptual diagram of a descriptor group set in the USB device.

Referring to FIG. 4, a descriptor group 400
Is composed of a device descriptor 401, a configuration descriptor 402, and a group of descriptors 403 to 404 describing an interface.

In FIG. 3, in a process 300, the descriptor conversion unit 213 analyzes the descriptor group of the connected USB device and searches for a communication service that can be provided by the USB device. After the search, in a process 301, each service is assigned to each USB host according to a predetermined correspondence table.

Further, in a process 302, an interface number related to the service is searched, and in a process 303,
Other interfaces, that is, descriptors not related to the service are deleted. After deletion, process 3
In step 04, when it is necessary to change the endpoint number or the like due to restrictions on hardware resources or the like, the descriptor is changed.

Subsequently, in steps 305 and 306, each USB
A new descriptor group is reconfigured as a dedicated descriptor group corresponding to the host, and is stored in the pseudo USB device function unit connected to each USB host. The conversion specification of the descriptor follows a correspondence table set in advance.

Next, the processing of the data transfer management section 212 will be described. By the above-described descriptor conversion processing, the service provided by the USB device connected to the lower port can be distributed to and supported by a plurality of USB hosts connected to the upper port.

However, unlike a hub that manages the association by the USB device address number, since the USB device is associated with a plurality of USB hosts by the interface number, data from the USB host connected to the upper port must be a pseudo USB device. Decoding and analysis are performed after the data is once received by the functional unit, and a new pseudo US
Control for sending a transmission request to the B host unit is required. The same applies to data from a USB device connected to the lower port.

The data transfer management unit 212 controls these transmission / reception requests. USB for each interface
It manages the correspondence between the host and the USB device, and performs conversion of the endpoint number and control of the data transfer route by the connection device and the interface number as necessary.

Further, the data transfer management unit 212
It also manages control when a USB host or USB device is connected to or disconnected from the B data conversion device 200. First, a process when the USB device is connected to the lower port of the USB data converter 200 or when the USB device is disconnected from the lower port will be described in detail with reference to a processing flowchart when the lower port is disconnected shown in FIG. I do.

When the USB device is connected to the lower port, the USB data converter 200 detects the change of the port by the pseudo USB host unit 215 in process 500 and recognizes the connection, and in device 501, the device configuration process ( USB
According to the standard, hereafter referred to as enumeration). At this time, descriptor information of the USB device is obtained.

Next, in process 502, the interface supported by the USB device is changed to the U port connected to the upper port.
Descriptor conversion is performed in order to allocate to the SB host, and the pseudo USB device function units 206 to 20 are respectively performed.
8 and store the descriptor group.

After the above processing is completed, in processing 503, the data transfer management section 212 turns on the pull-up resistor of the data line D + of the corresponding pseudo USB device function section. As a result, the USB host connected to the upper port
Recognition of the connection with the B device function unit enables communication.

Conversely, when the USB device connected to the lower port is disconnected or deconfigured, the processing 5
04, the data transfer management unit 212
The pull-up resistance of the data line D + in the device function section is turned off. This notifies the USB host connected to the upper port of the line disconnection.

Next, the processing when the USB host is connected to the upper port of the USB data converter 200 or when the USB host is disconnected from the upper port will be described with reference to the processing flowchart for disconnecting the upper port shown in FIG. I will explain it.

When a USB host is connected to the upper port, the pseudo USB device function unit detects a change in the USB bus in step 600 to recognize the connection of the USB host, and in step 601 enumeration by the USB host is performed. Will be Subsequently, by notifying the data transfer management unit 212 in the process 602, the US
Communication between the B host and the USB device connected to the lower port becomes possible.

Conversely, if the USB host connected to the upper port is disconnected or the pseudo USB device function unit is released, the processes 603 and 604 notify the data transfer management unit 212 and the pseudo USB host unit 215. I do. In step 605, the pseudo USB host 215 issues a vendor request to the USB device connected to the lower port, and notifies that the service related to the USB host has been stopped. As a result, without disconnecting communication with another USB host connected to the upper port, the corresponding U
Communication between the SB host and the USB device connected to the lower port is disconnected.

With the above configuration, an interface supported by a USB device is assigned to a plurality of USB hosts, and a plurality of USB hosts can simultaneously serve the same USB device. Disconnect, and US to lower port
For the connection / disconnection of the B device, the same operation as the normal connection / disconnection sequence can be performed.

Further, a hierarchical connection using such a USB device connection device will be described with reference to an example of a hierarchical connection configuration of the USB device connection device shown in FIG.

In FIG. 7, services S1, S2, S3
For one USB device 700 that supports
USB data converters 701, 702, 703, 704
Are hierarchically connected. USB data converter 70
Each of 1 to 704 has an application control unit 214 of a USB host mounted thereon, and can operate as a USB host that can independently provide a service.

Therefore, for example, only the USB data conversion device 701 can function as a USB host having an application, and a hierarchical USB host tree structure as shown in FIG. 7 can be constructed.
In other words, it is possible to realize a USB host that can easily expand the hierarchy with respect to one USB device that provides a plurality of services.
Series connection can be easily realized.

[0047]

As described above, according to the present invention,
A pseudo USB device function unit that holds the reconstructed descriptor and a pseudo USB host unit are built in the USB device connection device, and by controlling data transfer between the two, an interface that can be provided by the USB device is provided by a plurality of USB devices. Since a USB device can be assigned to a host, one USB device can be made to correspond to a plurality of USB hosts at the same time. That is, a plurality of USB hosts can simultaneously share a single USB device.

Further, according to the present invention, by incorporating a USB host and an application execution function,
The SB device connection device can behave as a host computer, and a USB device can be connected to a single USB device.
By adopting a configuration in which hosts are hierarchically expanded and connected, application tree structure and serial expansion can be easily realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration method of a USB system using a USB device connection device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a USB device connection device according to one embodiment of the present invention.

FIG. 3 is a flowchart illustrating a procedure of a descriptor conversion process.

FIG. 4 is a conceptual diagram of a descriptor group set in a USB device.

FIG. 5 is a processing flowchart when a lower port connection is disconnected.

FIG. 6 is a processing flowchart at the time of disconnecting an upper port connection.

FIG. 7 is an example of a hierarchical connection configuration of a USB device connection device.

FIG. 8 is a conceptual diagram illustrating a conventional method of sharing a USB device from a plurality of USB hosts.

[Explanation of symbols]

100, 200 USB data converter 101, 102, 103, 201, 202, 203 U
SB host 104, 105, 204, 205 USB device 206, 207, 208 Pseudo USB device function part 209, 210 Bus 211 CPU 212 Data transfer management part 213 Descriptor conversion part 214 Application control part 215 Pseudo USB host part 216, 217, 218 219, 220 Interrupt signal 400 Descriptor group 401 Device descriptor 402 Configuration descriptor 403, 404 Interface-related descriptor group 700 USB devices 701, 702, 703, 704 USB data converter

Claims (3)

[Claims] 1. A plurality of USB hosts and one or more USBs
A USB device connection device connected to a device, a plurality of pseudo USB device function units connected to the plurality of USB hosts, one pseudo USB host unit connected to the USB device, and the USB A descriptor conversion unit that generates a descriptor group describing a service provided by the device to each of the USB hosts and sets the descriptor group in the pseudo USB device function unit; the plurality of pseudo USB device function units and the pseudo USB
A USB device connection device, comprising: a data transfer management unit that controls data transfer to and from a host unit. 2. The method according to claim 2, wherein the descriptor conversion unit includes the US
From the descriptor group set in the B device, the U
2. The USB according to claim 1, wherein a descriptor is selected according to a service provided to each of the SB hosts, conversion is performed as necessary, and a reconfigured descriptor group is set in the pseudo USB device function unit. Equipment connection device. 3. The USB device connection device according to claim 1, further comprising a USB host application execution function.